In Exchange Rates I and Exchange Rates II, we discuss how to treat base malts and specialty grains when converting an all-grain recipe to an extract-based formulation. In an ideal world, malt extracts would all be made from 100 percent base malt, but this is rarely the case. Most malt extracts are produced using a blend of one or more base malts and some specialty grains, and the precise formulation varies from one manufacturer to the next.
The following table indicates the typical ingredients found in the most widely available malt extracts in the United States. Percentages are provided where possible. This list is not exhaustive, and you should ask your suppliers to provide information on the particular brands of extract they sell.
Liquid malt extract ---> Typical composition
Pilsner ---> Pilsner malt, Carapils
Pale ---> Pale malt, Carapils
Maris Otter ---> 100 percent Maris Otter malt
Amber ---> Pale malt, Munich malt, caramel 60
Dark ---> Pale malt, Munich malt, caramel 60, black malt
Munich ---> 50 percent pale malt, 50 percent Munich malt
Wheat ---> 65 percent wheat malt, 35 percent pale malt
Rye ---> 60 percent pale malt, 20 percent rye malt, 10 percent caramel 40
As you can see, the percentage of rye in rye malt extract is quite low, and there’s some caramel malt in there as well. You should take this into consideration when converting someone’s all-grain recipe for rye IPA to your own extract recipe. If the recipe calls for caramel malt, you might reduce the quantity you include to account for the fact that your malt extract already has some in it.
Similarly, Munich extract is actually made from 50 percent Munich and 50 percent pale malt. If you’re converting an Oktoberfest recipe that features 75 percent Munich malt, you won’t obtain the same results by substituting pound for pound.
Note also that amber and dark malt extracts contain unknown percentages of caramel and black malts. While it may be tempting to use these extracts to brew amber ales, porters, and stouts, a better option is to simply use pale malt or Munich extract and steep your own caramel malt, black malt, and roasted barley according to the kind of beer your’re making. This way you can more precisely control the outcome.
Another thing to consider is that the fermentability of extract is set at the time of manufacturing. This is typically around 75 percent and is meant to be an all-around compromise for different styles of beer. If you’re brewing a style that benefits from very high attenuation, such as saison and other Belgian styles, you may need to replace some of the malt extract with a simple sugar that will ferment completely.
Converting malts to malt extracts isn’t an exact science, and you may have to experiment for best results. In Exchange Rates IV, we discuss how to deal with adjuncts such as maize and oats.